The present disclosure relates generally to a system and method of measuring shims, such as shims for an aircraft assembly.
Aircraft manufacturing involves the assembly of many parts that are required to fit together within predetermined tolerances. Accordingly, shims are often utilized at interfaces between various parts to fill the gap between the parts and to ensure that the various parts fit together properly, as well as to facilitate proper load distribution between the parts.
Shims utilized to assemble various aircraft parts vary in size and complexity. For example, there are some parts that have substantially planar surfaces. Accordingly, shims having a substantially planar surface, referred to herein as flat shims, may be utilized. Moreover, other parts utilized to form the aircraft have complex shapes and surfaces. Therefore, the shims utilized between two parts having complex shapes or surfaces also have complex shapes and surfaces.
At least one known method of fabricating a shim includes manually measuring the gap between the two parts where a shim is to be installed. For example, a technician may initially draw a sketch of a shim to be installed. The technician may then manually reposition a mechanical device, such as a feeler gauge, to obtain a plurality of measurements at different locations within the gap. The technician then manually draws the measurements on the sketch. The sketch may then be utilized to hand cut the shim based on the measurements obtained. However, manually measuring the gaps and then hand cutting shims is often time consuming. For example, a typical process thus includes, gap measurements that are initially manually obtained, the shim is then trimmed, and the trimmed shim then re-installed into the desired gap. The process of manually measuring the gap and then hand trimming the shim may require several iterations to produce a shim that is sized to fit within a particular gap. Moreover, if the gap has a complex surface, the amount of time required to measure, trim and then install the shim is further increased.
Other known methods of fabricating a shim include using an electronic device to measure the gap. More specifically, a technician may again initially draw a sketch of a shim to be installed. The technician may then manually position the electronic device at a first location to obtain a first measurement, reposition the electronic device to a second location to obtain a second measurement, etc. The shim is then manufactured in the same manner as described above with respect to the manual measuring device.
However, both the mechanical measuring device and the electronic measuring device are configured to obtain a single measurement at a single location within the gap. Thus, to fabricate the shim, the user must manually reposition the mechanical or electronic device at various different locations within the gap. Additionally, the user must manually identify the exact location within the gap being measured, using for example the sketch, to enable the shim to be fabricated. As a result, both the mechanical measuring device and the electronic measuring device rely on the technician to manually reposition the device at the various locations to perform the measurements. Moreover, both the manual and electronic measurement devices rely on the technician's ability to accurately identify a location that the measurement is being performed to enable a shim to be manufactured. Accordingly, measuring the gap between two parts to fabricate a shim using either the mechanical device or the electronic device is both time consuming and may not result in measurements having a required precision to fabricate the shim.
The mechanic may also manually transfer the measurement points to a computer-aided design (CAD) model which may then be used to automatically machine shims using a numerical control (NC) machine.